// Copyright 2016 The Draco Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
#ifndef DRACO_COMPRESSION_ATTRIBUTES_PREDICTION_SCHEMES_PREDICTION_SCHEME_WRAP_ENCODING_TRANSFORM_H_
#define DRACO_COMPRESSION_ATTRIBUTES_PREDICTION_SCHEMES_PREDICTION_SCHEME_WRAP_ENCODING_TRANSFORM_H_

#include "draco/compression/attributes/prediction_schemes/prediction_scheme_wrap_transform_base.h"
#include "draco/core/encoder_buffer.h"

namespace draco {

// PredictionSchemeWrapEncodingTransform wraps input values using the wrapping
// scheme described in: prediction_scheme_wrap_transform_base.h .
template <typename DataTypeT, typename CorrTypeT = DataTypeT>
class PredictionSchemeWrapEncodingTransform
    : public PredictionSchemeWrapTransformBase<DataTypeT> {
  public:
    typedef CorrTypeT CorrType;
    PredictionSchemeWrapEncodingTransform() {}

    void Initialize(const DataTypeT *orig_data, int size, int num_components) {
        PredictionSchemeWrapTransformBase<DataTypeT>::Initialize(num_components);
        // Go over the original values and compute the bounds.
        if (size == 0)
            return;
        DataTypeT min_value = orig_data[0];
        DataTypeT max_value = min_value;
        for (int i = 1; i < size; ++i) {
            if (orig_data[i] < min_value)
                min_value = orig_data[i];
            else if (orig_data[i] > max_value)
                max_value = orig_data[i];
        }
        this->set_min_value(min_value);
        this->set_max_value(max_value);
        this->InitCorrectionBounds();
    }

    // Computes the corrections based on the input original value and the
    // predicted value. Out of bound correction values are wrapped around the max
    // range of input values.
    inline void ComputeCorrection(const DataTypeT *original_vals,
                                  const DataTypeT *predicted_vals,
                                  CorrTypeT *out_corr_vals) const {
        for (int i = 0; i < this->num_components(); ++i) {
            predicted_vals = this->ClampPredictedValue(predicted_vals);
            out_corr_vals[i] = original_vals[i] - predicted_vals[i];
            // Wrap around if needed.
            DataTypeT &corr_val = out_corr_vals[i];
            if (corr_val < this->min_correction())
                corr_val += this->max_dif();
            else if (corr_val > this->max_correction())
                corr_val -= this->max_dif();
        }
    }

    bool EncodeTransformData(EncoderBuffer *buffer) {
        // Store the input value range as it is needed by the decoder.
        buffer->Encode(this->min_value());
        buffer->Encode(this->max_value());
        return true;
    }
};

}  // namespace draco

#endif  // DRACO_COMPRESSION_ATTRIBUTES_PREDICTION_SCHEMES_PREDICTION_SCHEME_WRAP_ENCODING_TRANSFORM_H_
